The invention relates to an access point (AP) used in a wireless LAN system. The wireless LAN system, for example, includes a wireless private branch exchange network system.
A wireless LAN system includes wireless LAN switch controllers (“WLANSWs”, wireless LAN control devices), access points (APs), and stations (STAs) corresponding to wireless clients. User data (e.g., IP packet) to be exchanged between the stations is transferred to a wired network or a wireless network via the access points and the wireless LAN switch controllers.
Each access point is subordinate to a wireless LAN switch controller that belongs to the same subnet as that of the access point or a different subnet, and transfers user data sent from a subordinate station to the wireless LAN switch controller.
When an access point is newly connected to a network, the access point knows neither an IP address of the access point itself nor a wireless LAN switch controller to which the access point itself should be subordinate. Therefore, the access point functions as a dynamic host configuration protocol (DHCP) client to access a DHCP server provided in the network to obtain an IP address to be used by the access point itself (AP's IP-address automatic acquisition function).
Further, the access point accesses the DHCP server or a domain name system (DNS) server provided in the network to obtain an IP address of a master wireless LAN switch controller, stored in the DHCP server or the DNS server (master wireless LAN switch controller automatic detection function).
When the access point obtains an IP address of the access point from the DHCP server, if the IP address of the wireless LAN switch controller is stored in the DHCP server, the access point can obtain the IP address of the wireless LAN switch controller together with the IP address of the access point itself.
Further, when the access point accesses the DNS server, the access point can use the host name of the master wireless LAN switch controller, set by default (initially set) at the time of shipment of the access point from the factory, to obtain the corresponding IP address from the DNS server.
Then, the access point uses the obtained IP address to access the wireless LAN switch controller, and becomes subordinate to the wireless LAN switch controller through data exchange with the wireless LAN switch controller. After the process, the access point is capable of transferring user data.
In the conventional technology described above, the access point is subordinate to the wireless LAN switch controller that has the IP address obtained from the DHCP server or the DNS server.
However, depending on the installation position of the access point, the wireless LAN switch controller that has the IP address provided by the DHCP server or the DNS server may not necessarily be most appropriate. For example, even though a wireless LAN switch controller to which the access point can be subordinate exists near the access point (for example, in the same subnet), the access point may be subordinate to a remote wireless LAN switch controller that has been detected via the DHCP server or the DNS server.
In this case, in order to make the access point subordinate to the most appropriate wireless LAN switch controller, it is necessary to manually change the corresponding setting. Access points are usually installed at high and unobstructed locations, such as on the ceilings or wall surfaces in offices, in many cases in order to obtain a good wireless environment. It is thus significantly troublesome to manually change the setting for an installed access point. If there are a large number of access points that need setting changes, a considerably long working time is required.